Question 1

Which of the following best describes the difference between species richness and species diversity in a biological community?

Accepted Answer

Species richness measures the number of species present, while species diversity incorporates both the number of species and their relative abundance.

Question 2

A volcanic eruption creates a new island with no soil or life. Which ecological process will occur first as life begins to colonize this island?

Accepted Answer

Primary succession

Question 3

Which of the following is an example of a commensalism interaction?

Accepted Answer

Barnacles attaching to a whale, gaining a place to live while the whale is unaffected.

Question 4

According to the competitive exclusion principle, what is the likely outcome when two species occupy the exact same niche in a stable environment?

Accepted Answer

One species will outcompete and exclude the other from the niche.

Question 5

Which of the following best illustrates the concept of a keystone species?

Accepted Answer

The removal of sea otters leads to the destruction of kelp forests by unchecked sea urchin populations.

Question 6

Which of the following equations correctly represents the logistic growth model, which was observed in Gause’s Paramecium experiments?

Accepted Answer

$$\frac{dN}{dt} = rN \left(1 - \frac{N}{K}\right)$$

Question 7

Which of the following is an example of an inducible defense in plants?

Accepted Answer

Production of chemical toxins like nicotine only after herbivore attack.

Question 8

A researcher observes that after a wildfire, the first plants to colonize the area are small, fast-growing species with high seed dispersal. What term best describes these species?

Accepted Answer

Pioneer species

Question 9

Which of the following scenarios best demonstrates niche differentiation?

Accepted Answer

Five species of shorebirds feed in the same area but use different feeding techniques and locations.

Question 10

Which of the following is a characteristic of a biodiversity hotspot?

Accepted Answer

It contains at least 1500 endemic plant species and has lost at least 70% of its original vegetation.

Question 11

Which of the following best describes the outcome of a top-down trophic cascade in Yellowstone National Park after the reintroduction of wolves?

Accepted Answer

Elk populations declined, leading to increased growth of willows and aspen, which benefited beavers and other species.

Question 12

Which of the following is an example of mutualism?

Accepted Answer

Mycorrhizal fungi exchanging nutrients with plant roots.

Question 13

Which of the following best describes the difference between a fundamental niche and a realized niche?

Accepted Answer

A fundamental niche is the full range of conditions a species can tolerate, while a realized niche is the range it actually occupies due to competition.

Question 14

Which of the following is NOT a constitutive defense?

Accepted Answer

Production of toxins only after herbivore attack.

Question 15

Which of the following best describes the process of facilitation during ecological succession?

Accepted Answer

Early-arriving species make conditions more favorable for later species.

Question 16

Which of the following is a plausible explanation for why biodiversity is higher in tropical regions compared to polar regions?

Accepted Answer

Tropical regions have greater geographic variation and more stable climates, supporting more species.

Question 17

Which of the following best describes the coevolutionary arms race?

Accepted Answer

A cycle where consumers and prey evolve adaptations and counter-adaptations in response to each other.

Question 18

Which of the following is an example of bottom-up control in a community?

Accepted Answer

The abundance of primary producers determines the abundance of herbivores and higher trophic levels.

Question 19

Which of the following best describes the effect of disturbance on community structure?

Accepted Answer

Disturbance can change the distribution of living and nonliving resources, altering community composition.

Community Ecology: Species Interactions and Succession

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